Perillyl Alcohol Promotes Relaxation in Human Umbilical Artery.

BACKGROUND: Perillyl alcohol (POH) is a monoterpenoid found in plant essential oils and has been shown to relax murine vessels, but its effect on human vessels remains poorly studied. OBJECTIVE: The study aimed to characterize the effect of POH on human umbilical arteries (HUA). METHODS: Rings of HUA were obtained from uncomplicated patients and suspended in an organ bath for isometric recording. The vasorelaxant effect of POH in HUA was evaluated on basal tone and electromechanical or pharmacomechanical contractions, and possible mechanisms of action were also investigated. RESULTS: POH (1-1000 µM) altered the basal tone of HUA and completely relaxed HUA rings precontracted with KCl (60 mM) or 5-HT (10 µM), obtaining greater potency in the pharmacomechanical pathway (EC50 110.1 µM), suggesting a complex interference in the mobilization of extra- and intracellular Ca2+. POH (1000 µM) inhibited contractions induced by BaCl2 (0.1-30 mM) in a similar way to nifedipine (10 µM), indicating a possible blockade of L-type VOCC. In the presence of potassium channel blockers, tetraethylammonium (1 mM), 4-aminopyridine (1 mM), or glibenclamide (10 µM), an increase in the EC50 value of the POH was observed, suggesting a modulation of the activity of BKCa, KV, and KATP channels. CONCLUSION: The data from this study suggest that POH modulates Ca2+ and K+ ion channels to induce a relaxant response in HUA.

The preeclampsia condition alters external potassium-evoked contraction of human umbilical vessels.

INTRODUCTION: Pre-eclampsia (PE) is a disease of high incidence in parturients, that adversely affects both mother and fetus. Although PE prevalence is high, there are few studies on literature describing its etiology or its mechanism of action. Thus, the aim of this study was to elucidate PE-induced alterations of contractile reactivity in umbilical vessels. METHOD: Segments of human umbilical artery (HUA) and human umbilical vein (HUV) from neonates of normotensive or PE parturients were obtained and contractile responses measured with a myograph. The segments were allowed to stabilize (2 h) under 1.0, 2.0 and 3.0 g force (gf) at pre-stimulation and, then, were stimulated with high isotonic K+ concentrations ([K+]o; 10-120 mM). RESULTS: All preparations responded to increases in isotonic K+ concentrations. In HUA and HUV of neonates of normotensive parturients, and in HUV of neonates of PE parturients, the contraction saturated at nearly 50 mM [K+]o, while in HUA of neonates of PE parturients, saturation occurred at 30 mM [K+]o. Additionally, several differences between contractile responses of HUA and HUV from neonates of normotensive parturients and those from neonates of parturients with PE were observed. PE alters the contractile response of the HUA and HUV to increased [K+]o, and its contractile modulation by the pre-stimulus basal tension. Moreover, in HUA of PE, reactivity is decreased for 2.0 and 3.0 gf basal tensions and increased for 1.0 gf; in the HUV of PE condition, it is increased for all basal tensions. DISCUSSION: In conclusion, PE promotes several alterations in HUA and HUV contractile reactivity, vessels in which important circulatory alterations are known to occur.

Vasodilation promoted by (E,E)-farnesol involving ion channels in human umbilical arteries.

Background: (E,E)-farnesol is a sesquiterpene alcohol derived from plants and animals that exhibits pharmacological properties in the cardiovascular system. However, its effects on human umbilical vessels remain unknown. Purpose: Thus, this study aims to characterize the vasodilatory effect of (E,E)-farnesol in human umbilical arteries (HUA). Study design: The tissue is obtained from pregnant women over 18 years of age, normotensive, and without prepartum complications. After collected, the tissue was segmented and dissected to remove Wharton's jelly and obtain the umbilical arteries segments. Methods: HUA segments were isolated and sectioned into rings that were subjected to isometric tension recordings in an organ bath. Results: (E,E)-farnesol (1 µmol/L to 1 mmol/L) promoted vasodilatory effect in HUA preparations, affecting basal tone, and inhibiting the electromechanical coupling induced by KCl 60 mmol/L with greater potency (EC50 225.3 µmol/L) than the pharmacomechanical coupling induced by 5-HT 10 µmol/L (EC50 363.5 µmol/L). In the absence of extracellular calcium, pharmacomechanical coupling was also abolished, and contractions induced by CaCl2 or BaCl2 were attenuated by (E,E)-farnesol indicating a possible direct inhibition of L-type VOCC as a mechanism of the vasodilatory effect. The vasodilator efficacy of (E,E)-farnesol on reduction of vasocontraction induced by the presence of tetraethylammonium (1 or 10 mmol/L), 4-aminopyridine (1 mmol/L) and glibenclamide (10 µmol/L) suggesting a possible influence of different potassium channels (BKCa, KV and KATP). Conclusion: These results suggest that (E,E)-farnesol may be a promising pharmacological candidate for obstetric hypertensive disorders.

LC-MS Analysis and Antifungal Activity of Turnera subulata Sm.

Fungi of the Candida genus are responsible for invasive candidiasis, which affects people all over the world and has high mortality rates. This is due to their virulence factors, which give them great resistance and pathogenicity. In addition, the emergence of multidrug-resistant strains makes it difficult to treat these infections. In this way, natural products have emerged as an alternative to standard drugs, where plants known for their medicinal properties such as Turnera subulata become attractive to research. The present work aimed to analyze the ethanol extract of Turnera subulata leaves against standard strains of Candida albicans, Candida krusei and Candida tropicalis using broth microdilution techniques. The identification of the compounds in T. subulata leaves by LC-MS revealed the presence of a wide variety of substances such as carboxylic acids and terpenes, with flavonoids and fatty acids being more evident. The antifungal assays showed that the extract was not able to inhibit the growth of the tested strains at concentrations with a clinical relevance. However, at higher concentrations, it was able to inhibit the fungal dimorphism of C. albicans and C. tropicalis. It is possible that the T. subulata extract has potential as an inhibitor of fungal virulence factors without affecting the cell viability. Further research should be carried out in order to assess its inhibitory potential for other fungal virulence factors.

Characterization of the vasodilator effect of eugenol in isolated human umbilical cord arteries.

Eugenol (EUG) is a phenylpropanoid widely used in the food and cosmetic industries. It is commonly referred to in the literature by its biological activities such as antioxidant, anti-inflammatory, antimicrobial, and relaxing in organs of laboratory animals, especially in rodent vessels. However, its vasorelaxant potential in human tissue, has not been investigated. Thus, this study characterizes the vasodilatory effect of EUG in the human umbilical artery (HUA). HUAs were isolated, cleaned, sectioned (3-4 mm) and placed in an organ bath (10 mL Krebs Henseleit, 37 °C; and carbogenic mixture). EUG (100-1400 µM), obtained total relaxation of electromechanical contractions induced by KCl (60 mM), and pharmacomechanical contractions (30-1200 µM), induced by serotonin (10 µM) and by histamine (10 µM), showing statistically significant concentrations: 600 µM, 400 µM and 200 µM, and EC50 values: 759.8 ± 6.5 µM, 229.9 ± 7.9 and 279.0 ± 3.4 µM, respectively. EUG (1200 and 1400 µM) prevented the contraction promoted by BaCl2 (0.1-30 mM), similar to the effects of nifedipine (10 µM), sugesting the involvement of EUG in blocking VOCCs. In the presence of tetraethylammonium (10 µM), EUG (30-1200 µM) did not produce a total relaxation (88.6%), suggesting that an alternative pathway where potassium channels, may partially mediate EUG effect. In the presence of 4-aminopyridine (1 mM), glibenclamide (10 µM), and tetraethylammonium (1 mM), EUG relaxed HUAs 100%, although the pharmacological potency was statistically altered, demonstrating the participation of K+ channels (Kv, KATP, BKCa). Our data indicates that EUG has a vasorelaxant effect on HUAs, had a greater pharmacological potency in the serotoninergic pathway, showing effective participation of VOCCs and a partial modulation of K+ channels. These data suggest new possibilities for the use of EUG in human vascular dysfunctions, such as preeclampsia. More studies are necessary to confirm the safety and effectivity in future treatments.

Myorelaxant action of the Dysphania ambrosioides (L.) Mosyakin & Clemants essential oil and its major constituent α-terpinene in isolated rat trachea.

This study aimed to investigate the myorelaxant action of the Dysphania ambrosioides essential oil (EODa) and its major constituent α-terpinene on tracheal smooth muscle isolated from rats. In tracheal smooth muscle ex vivo, in organ baths, isometric contractions recordings were done in order to evaluated the effect of EODa (1-1000 µg/mL) and α-terpinene (1-3000 µg/mL) on the following parameters: basal tone, contractions evoked by potassium (KCl 60 mM), acetylcholine (ACh 10 µM) or serotonin (5-HT 10 µM). The EODa and its major constituent α-terpinene, did not statistically alter basal tone; however, they induced myorelaxant effects on top of contractions induced by KCl, ACh and 5-HT. EODa and α-terpinene also inhibited the contractions induced by barium in presence of High [K+] (80 mM). The data suggest that the relaxation induced by these agents is caused by the inhibition of L-type VGCC, inhibiting the inward Ca2+ current through these channels, but does not exclude the possibility of participation of other mechanisms. Results from this study also suggest the EODa, due to their efficacy on relaxation of the respiratory tract, posses a therapeutic potential as a antispasmodic agent for respiratory tract.

Tocolytic activity of the Lippia alba essential oil and its major constituents, citral and limonene, on the isolated uterus of rats.

The species Lippia alba (Mill.) N. E. Brown belongs to the Verbenaceae family. It is abundant and grows spontaneously throughout the Brazilian territory. Popularly known as "erva-cidreira", it is widely used because of its sedative, carminative and analgesic properties. The objective of this study was to investigate the mechanism of action of the L. alba essential oil (EOLa) and its major constituents citral and limonene, on isolated rat uterus muscle. To evaluate the EOLa, citral and limonene effect, cumulative concentrations curves for EOLa and citral (1-600 µg/mL) and for limonene (1-1200 µg/mL) were constructed from contractions of rat uterine strips under a 1 g tension. EOLa, citral and limonene dose-dependently relaxed myometrial preparations pre-contracted with 60 mM KCl, 10-2 IU/mL oxytocin, serotonin (10 µM), or ACh (10 µM). The results demonstrate that the EOLa, citral and limonene cause relaxation of the uterine smooth muscle. These results suggest that the relaxation induced by EOLa, citral and limonene is caused by inhibition of L-type VOCC, inhibiting the Ca2+ current through these channels, although other mechanisms of action are likely to contributing to relaxant activity. There was no involvement of K+ channels (BKca, KATP, KV) or cyclooxygenase on the relaxation promoted by EOLa. Then studies of the tocolytic effects of EOLa, citral and limonene may yield new insights into their therapeutic use.